/// <summary>
/// Implements applicative-order evaluation.
/// </summary>
/// <param name="env"></param>
/// <returns></returns>
public override IValue Evaluate(Environment env)
{
// Eval and get the operator
IValue procedure = ProcedureExpression.Evaluate(env);
// Both primitive & compound procedures are strict
var arguments = from argExpr in ArgumentExpressions
select argExpr.Evaluate(env);
switch (procedure)
{
case PrimitiveProcedure pproc:
return(pproc.Execute(arguments.ToList()));
case CompoundProcedure cproc:
return(cproc.Execute(arguments.ToList()));
default:
throw new RuntimeErrorException("procedure application", $"Expected a procedure that can be applied. Given: {procedure.Represent()}");
}
}
static void ProcedureProcessor(StringBuilder stringBuilder, ProcedureExpression expression, ShaderMetadata metadata)
{
// SWAP ARGUMENTS !!!
if (expression == null)
{
return;
}
// Pre process
// For procedure "tex2D"
if (expression.Name.Equals("tex2D") && metadata is PixelShaderMetadata)
{
// Cast to pixel metadata
var pixelMetadata = metadata as PixelShaderMetadata;
// Find tex2D syntax part
TextPart tex2DPart = expression.ConstituentSymbols[0] as TextPart;
// Find sampler name
TextPart samplerPart = expression.ConstituentSymbols[2] as TextPart;
// Find sampler expression
SamplerExpression samplerExpression = pixelMetadata.Samplers.Find(s => s.Name == samplerPart.TextValue);
if (samplerExpression == null)
{
throw new ArgumentNullException("samplerExpression");
}
// Find texture name
if (string.IsNullOrEmpty(samplerExpression.Resource))
{
throw new ArgumentNullException("samplerExpression.Resource");
}
// Modify
tex2DPart.TextValue = samplerExpression.Resource + ".Sample";
}
if (expression.Name.Equals("texCube") && metadata is PixelShaderMetadata)
{
// Cast to pixel metadata
var pixelMetadata = metadata as PixelShaderMetadata;
// Find tex2D syntax part
TextPart texCubePart = expression.ConstituentSymbols[0] as TextPart;
// Find sampler name
TextPart samplerPart = expression.ConstituentSymbols[2] as TextPart;
// Find sampler expression
SamplerExpression samplerExpression = pixelMetadata.Samplers.Find(s => s.Name == samplerPart.TextValue);
if (samplerExpression == null)
{
throw new ArgumentNullException("samplerExpression");
}
// Find texture name
if (string.IsNullOrEmpty(samplerExpression.Resource))
{
throw new ArgumentNullException("samplerExpression.Resource");
}
// Modify
texCubePart.TextValue = samplerExpression.Resource + ".Sample";
}
// Check for unsupport construct float4x4(n) in hlsl, so convert to (float4x4)n
if (expression.Name.Equals("float4x4"))
{
// Find float4x4 syntax part
TextPart float4x4Part = expression.ConstituentSymbols[0] as TextPart;
// Find value name
TextPart valuePart = expression.ConstituentSymbols[2] as TextPart;
if (valuePart != null &&
(valuePart.TextValue.Equals("0") || valuePart.TextValue.Equals(".0") ||
valuePart.TextValue.Equals(".0f") || valuePart.TextValue.Equals("0.0") || valuePart.TextValue.Equals("0.0f")))
{
// Remove procedur name and value => "()"
expression.ConstituentSymbols.Remove(float4x4Part);
expression.ConstituentSymbols.Remove(valuePart);
// Insert procedur name to bracket => (float4x4)
expression.ConstituentSymbols.Insert(1, float4x4Part);
// Insert value in last => (float4x4)n
expression.ConstituentSymbols.Add(valuePart);
}
}
// For other procedure .... like clamp, max, min, etc (in HLSL is not needed, maybe do it on GLSL)
// Main
CommonProcessor(stringBuilder, expression.ConstituentSymbols, metadata);
}
/// <summary>
/// Parses a procedure expression.
/// </summary>
public static void AcceptProcedure(string Text, int Start, out ProcedureExpression Expression, out int LastChar)
{
List<Statement> statements = new List<Statement>();
Statement statement;
if (AcceptStatement(Text, Start, out statement, out LastChar))
{
statements.Add(statement);
while (true)
{
int nc;
AcceptWhitespace(Text, LastChar, out nc);
if (AcceptStatement(Text, nc, out statement, out nc))
{
LastChar = nc;
statements.Add(statement);
}
else
{
Expression = new ProcedureExpression(statements);
return;
}
}
}
else
{
LastChar = Start;
Expression = new ProcedureExpression(new List<Statement>());
}
}